Catheters for the introduction or removal of fluids may be located in various venous locations and cavities throughout the body of a patient for introduction of fluids to the body or removal of fluids from the body. Such catheterization may be performed by using a single catheter having multiple lumens. A typical example of a multiple lumen catheter is a dual lumen catheter assembly in which one lumen introduces fluid and the other lumen removes fluid. An example of such a dual lumen catheter assembly is the SPLIT-CATH® catheter.
Generally, to insert any catheter into a blood vessel, the vessel is identified by aspiration with a long hollow needle in accordance with the well known Seldinger technique. When blood enters a syringe attached to the needle, indicating that the vessel has been found, a thin guidewire is then introduced, typically through a syringe needle or other introducer device into the interior of the vessel. The introducer device is then removed, leaving the guidewire within the vessel. The guidewire projects beyond the surface of the skin. At this point, several options are available to a physician for catheter placement. The simplest is to pass a catheter into the vessel directly over the guidewire. The guidewire is then removed, leaving the catheter in position within the vessel. However, this technique is only possible in cases where the catheter (for example, a small diameter dual lumen catheter) is of a relatively small diameter, made of a stiff material, and not significantly larger than the guidewire. If the catheter to be inserted is significantly larger than the guidewire, a dilator device with a sheath is passed over the guidewire to enlarge the opening in the vessel. The guidewire and dilator are then removed, leaving the sheath in position within the vessel. The catheter is then passed through the sheath into the vessel, and the sheath is removed by tearing the sheath and pulling the sheath out of the vessel around the catheter.
However, the designs of some existing multi-lumen catheters may induce turbulent flow through the catheter lumens, resulting in localized regions of reduced blood flow through the catheter lumens and a potential for the formation of blood clots in or near these regions within the catheter lumens. Also, some multi-lumen catheter designs have a lumen cross-sectional shape that allows blood clotting around the exterior of the catheter lumens within the patient's blood vessel. It would be beneficial to provide a multi-lumen catheter with improved flow capability and which decreases the likelihood of blood clotting within the catheter lumens or around the exterior of the catheter.